(Un)Coupled thrust belt-foreland deformation in the northern Patagonian Andes: New insights from the Esquel-Gastre sector (41°30′–43°S)

Authors
Savignano, E.; Mazzoli, S.; Arce, Luis Martin; Franchini, Marta Beatriz; Gautheron, C.; Paolini, M.; Zattin, M.
Publication Year
2016
Language
English
Format
article
Status
Published version
Description
The Patagonian Andes represents a unique natural laboratory to study surface deformation in relation to deep slab dynamics. In the sector comprised between latitudes 41°30′ and 43°S, new apatite (U-Th)/He ages indicate a markedly different unroofing pattern between the “broken foreland” area (characterized by Late Cretaceous to Paleogene exhumation) and the adjacent Andean sector to the west, which is dominated by Miocene-Pliocene exhumation. These unroofing stages can be confidently ascribed to inversion tectonics involving reverse fault-related uplift and concomitant erosion. Late Cretaceous-Paleogene shortening and exhumation are well known to have affected also the thrust belt sector of the study area during a prolonged stage of flat-slab subduction. Therefore, the different ages of near-surface unroofing documented in this study suggest coupling of the deformation between the thrust belt and its foreland during periods of flat-slab subduction (e.g., during Late Cretaceous-Paleogene times) and dominant uncoupling during periods of steep-slab subduction and rollback, even when these are associated with high convergence rates (i.e., > 4 cm/yr), as those documented in Miocene times for the Patagonian Andes.
Fil: Savignano, E.. Università di Padova; Italia
Fil: Mazzoli, S.. Università degli Studi di Napoli Federico II; Italia
Fil: Arce, Luis Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad Nacional de Río Negro; Argentina
Fil: Franchini, Marta Beatriz. Universidad Nacional del Comahue; Argentina. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina
Fil: Gautheron, C.. Universite Paris-sud Xi;
Fil: Paolini, M.. Pan American Silver; Argentina
Fil: Zattin, M.. Università di Padova; Italia
Subject
AHE DATING
BROKEN FORELAND
CHUBUT
EXHUMATION
LOW-TEMPERATURE THERMOCHRONOLOGY
PATAGONIA
Meteorología y Ciencias Atmosféricas
Ciencias de la Tierra y relacionadas con el Medio Ambiente
CIENCIAS NATURALES Y EXACTAS
Access level
Open access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/77767